Apparatus for automatically mixing a cleaning solution for automatic cleaning equipment for dairies or the like

ABSTRACT

Apparatus which automatically mixes various components such as detergent, acid, and water or other ingredients in proper sequence and amounts to form a cleaning solution for cleaning-inplace milk line equipment, bulk storage tanks or other equipment. The apparatus includes a pump that can be adjusted so as to draw a predetermined amount of material from a storage container and then dispenses that amount of material into another receptacle for mixing with other components to form the cleaning solution; the material withdrawn from the storage container does not enter the pump and consequently, for example if acid is used, it does not deteriorate the pump. Instead the material is drawn from the storage container into a conduit and then suitable valves permit the fluid to be discharged from the conduit directly into the mixing container. The capacity of the pump can be varied by an adjustable eccentric and the pump capacity is so sized, in relationship to the conduit through which it draws the material out of the storage tank, that the material does not enter the pump. A number of such pumping apparatus are used to pump the various materials from their individual storage containers and into the mixing tank to form the cleaning solution.

United States Patent 11 1 Schmid [451 Nov. 25, 1975 1 1 APPARATUS FOR AUTOMATICALLY MIXING A CLEANING SOLUTION FOR AUTOMATIC CLEANING EQUIPMENT FOR DAIRIES OR THE LIKE [75] Inventor: Rolyn A. Schmid. Hayward, Wis.

[73] Assignee: Bender Machine Works, Inc.,

Hayward, Wis.

[22] Filed: Sept. 30, 1974 [21] Appl. No; 510,314

Primary Examiner-Robert L. Bleutge Attorney. Agent, or Firm.lames E. Nilles [57] ABSTRACT Apparatus which automatically mixes various components such as detergent, acid. and water or other ingredients in proper sequence and amounts to form a cleaning solution for cleaning-in-place milk line equipment, bulk storage tanks or other equipment. The apparatus includes a pump that can be adjusted so as to draw a predetermined amount of material from a storage container and then dispenses that amount of material into another receptacle for mixing with other components to form the cleaning solution; the material withdrawn from the storage container does not enter the pump and consequently, for example if acid is used, it does not deteriorate the pump. Instead the material is drawn from the storage container into a conduit and then suitable valves permit the fluid to be discharged from the conduit directly into the mixing container. The capacity of the pump can be varied by an adjustable eccentric and the pump capacity is so sized, in relationship to the conduit through which it draws the material out of the storage tank, that the material does not enter the pump.

A number of such pumping apparatus are used to pump the various materials from their individual storage containers and into the mixing tank to form the cleaning solution.

7 Claims, 11 Drawing Figures US. Patent Nov. 25, 1975 Sheet 1 of5 3,921,652

U.S. Patent Nov. 25, 1975 Sheet2of5 3,921,652

U.S. Patent Nov. 25, 1975 Sheet 3 of5 3,921,652

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U.S. Patent Nov. 25, 1975 Sheet 5 of5 3,921,652

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APPARATUS FOR AUTOMATICALLY MIXING A CLEANING SOLUTION FOR AUTOMATIC CLEANING EQUIPMENT FOR DAIRIES OR THE LIKE BACKGROUND OF THE INVENTION Many types of dairy equipment or other equipment are required to be cleaned-in-place and this cleaning must be made frequently in order to comply with the sanitation laws of the various states. Various materials must be used in the cleaning solution to insure absolute cleaning of the interior of the pipes, etc., for example, an acid must be used to cut the residue milk from the pipes in milking systems. A detergent is also used to thoroughly clean the equipment and when the cleaning cycle is finished, the system must be flushed with clear water and then preferably sanitized. As a result, various sequences of cleaning operations must be performed in timed relationship in such equipment. One example of milk line equipment with which the present invention finds utility is shown in the U.S. Pat. No. 3,l9l,576 issued June 29, I965 to L. F. Bender and entitled Milk Line Releaser and Washing Apparatus. That apparatus utilizes automatically operated releaser apparatus of the vacuum type and in which the cleaning solution is held in a large tank and circulated through the milk line and vacuum releaser apparatus to thoroughly clean the same.

Another example of equipment with which the present invention finds utility is shown in U.S. Pat. No. 3,802,447, issued Apr. 9, 1974 to L. F. Bender and entitled Automatic Tank Washer and Spin-Burst Mechanism for Washing, Rinsing, and Sanitizing. That apparatus automatically washed milk storage tanks by means of appropriate steps in a washing cycle.

SUMMARY OF THE INVENTION The present invention provides apparatus for automatically mixing components ofa cleaning solution and in proper sequence and amounts and the solution is then used in various equipment such as automatic cleaning equipment for dairies or the like.

The apparatus includes a piston type pump which is adjustable as to the volume of material it can extract from a storage container, the material is not drawn into the pump to contaminate it, and the material is then discharged from an intervening conduit and into a mixing tank or the like to form a cleaning solution with other materials. A number of such pumps and their respective storage tanks are usable with the present invention and are all actuated in timed sequence by a timing device such as an electric timer that drives various cams that in turn operate the motors that drive the pumps.

The piston type pump provided by the present invention can be easily assembled and disassembled and its piston is spring actuated in one direction by a spring, which spring is located outside of the pumping chamber to insure its cleanliness, and to insure that liquid condensation or vapor does not cause it to deteriorate. The conduit which connects the pump to the material storage container is of such internal volume that the maximum displacement of the pump, regardless of its capacity adjustment, insures that liquid being pumped never enters the pumping chamber and the movement of the liquid is accomplished by the medium of the air which is trapped in the pumping chamber of the pump.

The storage container of the material has a one-way valve therein which permits the material to be withdrawn from the container by the pump and prevents the material from being discharged into the container by the pump. The pump then pumps the withdrawn material into the mixing tank for forming a cleaning solution with other materials.

The automatic equipment provided by the present invention utilizes a number of pumps of the above character and which are controlled by an external timing device so that various materials, such as detergent, acid and sanitizers can be added at the proper time and in the proper amount. The apparatus requires no daily intervention on the part of the operator and it is only necessary for him to replenish the supply of various material in their respective storage containers at periodic intervals.

These and other objects and advantages of the present invention will appear hereinafter as this disclosure progresses, reference being had to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is a cross sectional, elevational view of the ap paratus for automatically mixing a cleaning solution in accordance with the present invention;

FIG. 2 is an enlarged, fragmentary elevational view taken generally along the line 2-2 in FIG. I and showing the adjustable eccentric means and the upper portion of the pump;

FIG. 3 is an enlarged. exploded view of portions of the one-way valve shown in the lower end of the storage container in FIG. I:

FIG. 4 is a view taken along the line 44 in FIG. 3;

FIG. 5 is an enlarged. exploded view of the check valve shown in the conduit in FIG. I;

FIG. 6 shows a plurality of cleaning apparatus as shown in FIG. 1 when used in cleaning a bulk tank;

FIG. 7 is an electric circuit of the control device of the present invention;

FIG. 8 is a sequential timing chart for the apparatus shown in FIGS. 6 and '7;

FIG. 9 shows the present invention when used for cleaning dairy fluid line equipment;

FIG. 10 is an electrical diagram of the circuits used with the invention when used in the FIG. 9 apparatus, and

FIG. ll is a sequential timing chart of the apparatus shown in FIGS. 9 and 10.

DESCRIPTION OF A PREFERRED EMBODIMENT FIG. 1 illustrates one of the pumping apparatus used with the present invention. A separable container 1 is used for each of several materials of which a cleaning solution is comprised. Any number of these containers may be used along with their individual pump and these materials may comprise a detergent, an acid, a sanitizer, or other chemicals. Furthermore, these containers may be of various sizes and large enough so that the operator need replenish them infrequently. The apparatus also includes an extensible and contractable piston type pump 2 which includes a plastic cylinder 3 in which a reciprocating piston 4 is mounted so as to form a pumping chamber 5 therebetween. The cylinder has an outwardly flared flange 3a turned around one end and the piston is made of plastic and has a radial flange 4a around one end. The pumping unit is extended by a spring 6 located outside the pump and encircling the piston and acting between the flange of the cylinder and piston. The pump is thereby easy to assemble and disassemble and readily cleaned. The spring cannot be subjected to the material it is pumping.

The pumping stroke is applied to the piston by an eccentric 7 driven by shaft 8 from the electric motor 9. The throw of the rotary eccentric 7 is adjustable by means of adjusting the rotary inner eccentric portion 10 relative to the outer portion II and suitable set screws are provided, as shown, for locking the portions in the desired position relative to one another. The eccentric contacts the upper end of the plunger for driving it in a pumping direction. The chamber 5 is connected by means of a flexible conduit 13 to a Y fitting 14 which in turn is connected by a tube 15 within the vessel. The tube 15 has a one-way check valve 16 located at its lower end and at the bottom of the interior of the container 1. This check valve is shown in detail in FIG. 3 and includes a shiftable, tapered valve element 17 that seals against a corresponding seat 18 of the lower portion 19 of the valve. The upper portion 20 of the valve surrounds the valve element 17 and the bore 20a of portion 20 is press-fit onto the annular surface 21 of the portion 19 of the valve. The other leg of the Y fitting 14 is connected by another conduit 23 that acts to carry the discharged fluid as will appear, to a vessel or other tank, to be described, where the mixing of the various fluid materials takes place to form a cleaning solution. The conduit 23 has a one-way check valve 25 located therein and this valve is shown in detail in FIG. 5. The valve 25 includes a disc 26 that seats against an internal surface 27 of the lower portion 28 of the valve so as to prevent return of fluid in one direction, that is downwardly into the container 1. An upper portion 29 has a reduced part 30 which is removably pressed into the bore 3| of the lower portion 28. Spaced apart feet 32 on the end of part 30 prevent disc 26 from sealing against portion 29.

The action of the pump is such that when the pump is extended by the spring 6, it acts to draw fluid through the valve l6 in the bottom of the container I and upwardly into the conduit 13. The volume of the conduit I3 is of such a volume, compared to the capacity of the pump, so that the material sucked up by the pump does not enter the pump chamber 5. When the motor 9 then drives the plunger inwardly to effect a pumping stroke, valve I6 closes and the fluid is pumped upwardly through the conduit 23, through the one-way check valve 25, and into the mixing tank to be referred to. When the pump 2 is extended to again effect a suction stroke, the one-way valve 25 closes and valve I6 opens.

The pump includes sealing rings 8 to form an air-tight seal due to the compression of the O-rings 8 between the piston and cylinder.

FIGS. 6 8 ENVIRONMENT The apparatus shown in FIG. 6 illustrates one form of equipment with which the present invention is used.

As previously mentioned, several of the apparatus as shown in FIG. I are usable with the present invention. one for each of any number of materials to be mixed into a cleaning solution. The motors 9 of the various apparatus are operated in timed sequence by cams driven by a timer as will appear.

A series of pumping apparatus as in FIG. I are shown as they are physically arranged in a control box 35 in FIG. 6. It will be noted that a number of containers 1, la, and lb each have, respectively, pumps 2, 2a and 2b which in turn are actuated by the electric motors 9, 9a. and 9b. The three pumping apparatus shown in FIG. 6 are each similar to one another and a further description of them is not believed to be either necessary or desirable. For purposes of describing the invention. assume that pump 2 and its motor 9 are for a detergent material. pump 2a and the motor 90 are for an acid material, and pump 2b and its motor 9b are for a sanitizer material.

It is believed sufficient to say that the conduits 23, 23a, and 23b from the three containers discharge into a common mixing tank. and in FIG. 6 this mixing tank takes the form of a chamber C.

The washing unit includes a support frame F fabricated from steel tubing or the like. The control box 35 is rigidly supported on the frame and has a pair of water hoses 40 and 41 extending therefrom for detachable connection to conventional spigots (not shown), respectively, of conventional cold and hot water lines which furnish the necessary water. Also supported on the frame is a conventional electric motor driven fluid pump 43 of the impeller type having its outlet connected to a conduit 44 for delivering the water to the upper side of a tank 45 to be cleaned. The inlet of the fluid pump is connected by a conduit 47 to a nipple 48 in the lower side of the regulating chamber C.

The regulating chamber C is generally cylindrical in shape. upright and may be open at its top. Chamber C is provided at its lower end with a generally cylindrical hollow extension 49 having a regulating chamber drain opening 50 at its upper end and a tank drain opening SI at its lower end. The sides of the openings 50 and SI form valve seats for vertically shiftable valve elements in the form of a regulating chamber drain stopper S2 and a tank drain stopper 53, respectively. The bottom of chamber C is provided with a drain hole 54.

The drain stoppers S2 and 53 are connected to the lower end of a stopper rod 55 that extends centrally down into the chamber. The stoppers 52 and 53 are conical in shape and may be of resilient material for good seating. such as rubber. The rod is vertically shiftable and a spring 56 biases the rod downwardly. The rod is raised by the action of the electric solenoid 57 connected to the top end of the rod. The drain solenoid 57 is energized by an electric timer T and its cam t3. (FIG. 7).

When rod 55 is raised by energization of solenoid 57, stopper S2 is raised to open regulating chamber drain opening 50 and stopper 53 is raised to close tank drain opening 5]. When rod 55 is lowered by deenergization of solenoid 57, stopper S2 is lowered to close regulating chamber drain opening 50 and stopper 53 is lowered to open tank drain opening SI, as FIG. 6 shows.

The timer T includes cams t1, t2, t3, t4, and t5 for op erating the various components, also in the control box. to be described. The timer T is set by a control knob K on the side of the control box 35.

As FIG. 7 shows. the timer T and cam t1 control energization of pump contactor coil 60 of a contactor 62 for operating motor PM for pump P; cam t2 controls energization of the solenoids 63 and 64 for the mixer valve 65 and the hot water valve 66, respectively; cam t3 controls energization of the drain solenoid 57; and cam t4 controls energization of the timer motor TM. Energization of timer motor TM is also controlled by pressure switch 84, as hereinafter explained. An on-off toggle switch 68 is provided, as well as conventional ac power source comprising supply lines L1, L2 and N.

The extension 59 of chamber C also has a nipple 70 between openings 50 and 51 and the passage 71 of the tank 45 is in fluid communication, via conduit 72, with the nipple 70 and chamber C.

Thus, the general flow of fluid is from the supply spigots (not shown), through a mixer valve 65 (operated by a solenoid 63), and down a liquid feeder tube 78 into the chamber C. Water from the hot water line 41 can also be diverted by hot water valve 66 operated by solenoid 64, through a conduit 81 and into chamber C.

It should be noted that the height of the regulating chamber C is set relative to tank 6 being cleaned so that the fluid level in the tank is regulated to, that is the same as, the level of the fluid in chamber C.

The fluid level is controlled or regulated by the level of the fluid in chamber C. Therefore, height of the chamber inlet 70 is about 4 to 8 inches lower than tank outlet 71. For example, assuming the stopper 52 is down and thus closes the discharge outlet 50 of the chamber, the level of the fluid in the chamber C is controlled by a normally closed pressure switch 84 which switch causes closing of the solenoid operated water valve. The switch 84 is actuated by the height of the fluid in a pressure tube 85 extending from the pressure switch downwardly into the chamber. The switch 84 regulates the water valves and consequently the flow of the water to chamber C. The extent to which the pres sure tube extends into the chamber determines the height to which the chamber will fill, and this setting need not be adjusted.

An example of a typical cycle of operation is as follows. Assume that unit U and tank 45 are connected, as shown in FIG. 6; that on-off toggle switch 68, shown in FIG. 7 is closed; that the hot and cold water hoses 41 and 40 are being charged with water; and that chamber C is empty.

In order to start the cycle. The cams t1 and t2 must be in a position wherein coil 60 of contactor 62 is connected to contact PS3 of pressure switch 84 and wherein solenoid coil 63 of mix valve 65 is connected to contact PS2 of pressure switch 84. Normally, the cams t1 and t2 assume this position when control knob K of timer T is turned to on" position. At this point.

cam t3 assumes a position wherein solenoid coil 57 is de-energized and, therefore. regulating chamber drain opening 50 is closed by stopper 52 and tank drain opening 51 is open. At this point cam t4 assumes a position wherein timer motor TM is not connected directly to line L]. Since chamber C is empty (any water therein having drained out through hole 54), pressure switch 84 connects its contact PS1 to contact PS2 and solenoid 63 for mix valve 65 is energized.

With mix valve 65 open, clean water (at a temperature of 95F, for example, for cleaning milk from tank 45), enters chamber C and begins to fill it to line F1. When the water rises to line Fl, pressure switch 84 operates to disconnect its contact PS1 from contact PS2 and to connect contact PS1 to contact PS3 with the following results: solenoid 63 deenergizes and closes mix valve 65 thereby stopping water flow into chamber C; contactor coil 60 energizes to close contactor 62 and starts pump motor PM and pump P driven thereby; and timer motor TM is energized and beings to drive all of its cams.

With pump P in operation, rinse water is pumped from chamber C through hoses 47 and 44 into tank 45. From tank 45, the rinse water drains through hose 72 and out tank drain opening 51 which is open. When the water level in chamber C is pumped down to level F3, pressure switch 84 operates to disconnect its contact PS1 from contact PS3 and to connect contact PS2 to contact PS2 with the following results: solenoid 63 energizes to open mix valve 64 to again start water flow into chamber C; contactor coil 60 de-energizes to open contactor 62 and stops pump P; and timer motor TM is de-energized and stops driving its cams.

The foregoing operation, wherein the chamber C is alternately filled and emptied several times. may be referred to as the spin-burst portion of the first rinse cycle and occurs during the first two minutes, for example. of the cycle, as FIG. 8 shows. During this first two minutes, timer motor TM is energized several times and finally drives its cams into a condition wherein cam t4 maintains timer motor TM connected to line L1, while the other cams cause their contacts to open.

As shown in FIG. 7, timer 5 operates the detergent motor 9, the acid motor 90, and the sanitize motor in the sequence indicated by the timing chart shown in FIG. 8.

FIG. 8 shows the timing sequence of the various operations and the various cycles involved in the equipment cleaning operation.

FIGS. 9-11 The invention has been shown in FIGS. 9 to 11 as applied to a milk line system located in a dairy barn for example, and of the general type shown in the said US. Pat. No. 3,l9l ,5 76 and particularly in FIG. 8 thereof. It is believed sufficient to say for purposes of this disclosure that the milk line system includes a solution tank on which the control box 35 is mounted. A continuous milk line 102 runs throughout the dairy barn and has a series of nipples 103 connected thereto and to which are connected the milking units (not shown). A flexible conduit 104 conveys the fluid from the tank 100 through a manifold 106 and to the milk line 102. A vacuum receiver receives the fluid from line 102 in its upper bowl 106. The receiver 105 is of a two bowl type and also includes a lower bowl 107 which is in communication with the upper bowl which includes a check valve 108 in the connecting neck 109. As clearly taught in said US. Pat. No. 3,191,576, a vacuum pump 110 draws a continuous vacuum through line 112, which line is connected by means of a slide valve 114 to each of conduits 116 and 118. Conduit 118 is in communication with the upper bowl 106 which conduit 116 is in communication with the lower bowl 107. The valve 114 is automatically shifted by a timing means as taught in said 576 patent so that the upper bowl 106 is subjected to a continuous vacuum while the lower bowl 107 is subjected alternately to atmospheric pressure and then to a vacuum. The action is such that the vacuum receiver 105 acts to periodically draw slugs of fluid from the line 102 and then when the receiver is full, it permits the fluid to be discharged back into the tank via conduit 120. In this manner, the vacuum receiver 105 which is actuated by the vacuum pump 110, acts to pull cleaning fluid through the line 102 and then return the fluid via conduit 120 to the tank 100. As the above operation is fully shown and described in the said '576 patent, further description is not believed to be necessary.

The manifold 106 is provided so that any number of a series of teat cup assemblies may be placed in communication with the manifold by means of a conduit 132. The teat cup assemblies themselves are of conventional character and may be of the type shown in US. Pat. No. 3.173.434 issued Mar. 16, 1965 to Lloyd F. Bender. Thus. any number of teat cup assemblies may be connected to the manifold and the cleaning fluid is drawn up through the cleaning assemblies for complete cleaning thereof. in addition to the cleaning operation of the milk line 102.

The electrical circuit shown in FIG. 10 is generally the same arrangement as shown in the FIG. 7 circuit and includes the timer motor TM and the five cams driven by the timer motor which cams in turn operate certain of the various components as heretofore described. It will be noted however. that the drain solenoid 136 for the drain rod 55 of the tank 100 is operated by the timer tl. The contactor solenoid 140 is also operated by the timer t1. The detergent motor 138 and the acid motor 9a are operated by the timer t3, while the sanitize motor 141 is operated by the timer t5. Parts similar in FIG. 10 to those shown in FIG. 7 are correspondingly numbered.

FIG. II shows the timing chart for the various components shown in FIG. I and illustrate the sequence and time of operation of the various components for the various phases of operation of a washing program.

GENERAL The present invention as above described includes a control system having a series of plunger type pumps which each in turn have their own separate containers from which they draw material that is mixed to define a cleaning solution. The pumps are operated by electric motors which in turn are programmed by a timer. The system also includes a fluid moving device and in FIGS. -7, this is comprised of a pump 43 driven by the pump motor PM whereas in the FIGS. 9-11 embodiment. the fluid moving device is the vacuum releaser 120 which is driven by the vacuum pump 110. Other forms of fluid moving devices may be utilized with the present invention such as agitators in a vessel to be washed. In either embodiment, the fluid moving device is controlled by an electrical contactor means.

I claim:

1. Control apparatus for automatically preparing a washing solution and also for cleaning equipment, said apparatus including a plurality of plunger type pump means each including an electric motor for driving said pump means in a fluid pumping direction, a fluid container for each of said pump means, a first conduit between the interior of each of said containers and its respective pump means whereby said pump means can draw fluid from its container and into its first conduit. one-way valve means in each of said first conduits. a second conduit extending from each of said first conduits and in communication therewith and for discharging fluid into a mixing tank or the like. a timer motor having a connection with said electric motors of said pump means so as to operate said pump means in programmed relationship to one another and thereby pump various materials into said mixing tank or the like. the solenoid operated valve means operated by said timer motor for permitting water to be conducted into said mixing tank to thereby form a washing solution with said various fluids. and a fluid moving device for conveying said solution through said equipment to be cleaned. and an electrical contactor means for controlling said fluid moving device.

2. The apparatus set forth in claim 1 further characterized in that said fluid moving device comprises a fluid pump and said equipment to be cleaned is a bulk tank.

3. The apparatus set forth in claim 1 further characterized in that said fluid moving device is a vacuum receiver and a vacuum pump for said receiver, and said equipment to be cleaned is an in-place milk line system.

4. The apparatus set forth in claim 1 further characterized in that said cylinders have an outwardly flared flange at one end and said pistons also have an outwardly extending flange, said spring means encircling said pumps and acting between the flanges of their respective said piston and cylinder.

5. The apparatus set forth in claim 1 further characterized in that said eccentric means include a rotary inner eccentric portion fixed to a shaft of said electric motor and also include an outer portion adjustably fixed to said inner portion.

6. The apparatus set forth in claim 4 further characterized in that said eccentric means includes a rotary inner eccentric portion fixed to a shaft of said electric motor and also includes an outer portion adjustably fixed to said inner portion.

7. The apparatus set forth in claim 4 further characterized in that said cylinder is formed of plastic and its flange is formed by being turned outwardly at one end, and said piston is formed of plastic and its flange is integrally formed at one end thereof, and an O-ring sealing means carried by said periphery of said piston and for sealing engagement with the interior of said cylinder. 

1. Control apparatus for automatically preparing a washing solution and also for cleaning equipment, said apparatus including a plurality of plunger type pump means each including an electric motor for driving said pump means in a fluid pumping direction, a fluid container for each of said pump means, a first conduit between the interior of each of said containers and its respective pump means whereby said pump means can draw fluid from its container and into its first conduit, one-way valve means in each of said first conduits, a second conduit extending from each of said first conduits and in communication therewith and for discharging fluid into a mixing tank or the like, a timer motor having a connection with said electric motors of said pump means so as to operate said pump means in programmed relationship to one another and thereby pump various materials into said mixing tank or the like, the solenoid operated valve means operated by said timer motor for permitting water to be conducted into said mixing tank to thereby form a washing solution with said various fluids, and a fluid moving device for conveying said solution through said equipment to be cleaned, and an electrical contactor means for controlling said fluid moving device.
 2. The apparatus set forth in claim 1 further characterized in that said fluid moving device comprises a fluid pump and said equipment to be cleaned is a bulk tank.
 3. The apparatus set forth in claim 1 further characterized in that said fluid moving device is a vacuum receiver and a vacuum pump for said receiver, and said equipment to be cleaned is an in-place milk line system.
 4. The apparatus set forth in claim 1 further characterized in that said cylinders have an outwardly flared flange at one end and said pistons also have an outwardly extending flange, said spring means encircling said pumps and acting between the flanges of their respective said piston and cylinder.
 5. The apparatus set forth in claim 1 further characterized in that said eccentric means include a rotary inner eccentric portion fixed to a shaft of said electric motor and also include an outer portion adjustably fixed to said inner portion.
 6. The apparatus set forth in claim 4 further characterized in that said eccentric means includes a rotary inner eccentric portion fixed to a shaft of said electric motor and also includes an outer portion adjustably fixed to said inner portion.
 7. The apparatus set forth in claim 4 further characterized in that said cylinder is formed of plastic and its flange is formed by being turned outwardly at one end, and said piston is formed of plastic and its flange is integrally formed at one end thereof, and an O-ring sealing means carried by said periphery of said piston and for sealing engagement with the interior of said cylinder. 